Flat-slab construction



R. M. HARDISON FLAT SLAB CONSTRUCTION Aug. 18, 1925.

2 Sheets-Sheet l Filed Feb; 2'7, 1922 I Ti/veW/iar ZePZMIIardIJG on illAug. 18, 1925. 1,550,317

v R. M. HARDISON FLAT SLAB CONSTRUCTION Filed Feb. 27. 1922 2Sheets-Sheet 2 BoZw-rZMHarddson,

Patented Aug. 18, 1925.

UNITED STATES I PATENT OFFICE.

ROBERT M. HARDISON, E BOSTON, MASSACHUSETTS, ASSIGNOR, BY MESNE ASSIGN-MENTS, TO' KALMAN STEEL COMPANY, OF CHICAGO, ILLINOIS, A CORPORATION OFDELAWARE.

FLAT-SLAB CONSTRUCTION.

Application filed February 27, 1922. Serial No. 539,373.

To all whom it may concern:

Be it known that I, ROBERT M. HARDIsoN, a citizen of the United States,and a resident of Boston, in the county of Suffolk and State ofMassachusetts, have invented an Improvement in Flat-Slab Constructions,of

which the following description, in connection with the accompanyingdrawings, is a specification, like characters on the drawingsrepresenting like parts.

This invention relates to reinforced concrete constructions and moreparticularly to fiat-slab constructions, that is to say to that type ofbuilding construction employing a reinforced concrete slab in which theload upon the floor is carried directly to the slab-supporting member,which may be a concrete or other column or any other suitable support.

The invention and its aims and objects will be readily understood fromthe following description, taken in connection with the accompanyingdrawings of one illustrative embodiment of the invention, the inventionin its true scope beingmore particularly set forth in the appendedclaims.

In the drawings:

Fig. 1 is a top plan view of one illustrative embodiment of theinvention;

Fig. 2 is a lateral sectional elevation of the embodiment shown inFig.1;

Fig. 3 is a lateral sectional elevation of a modified construction; andw Fig. 4 is a lateral sectional elevation of a further modification. V

Referring to the accompanying drawings, 2 indicates a concrete slab and4 a concrete column. The head to be anchored in the slab will preferablycomprise two spaced metal members, separated by one or more other metalmembers rigid therewith. In the embodiment of the invention hereinillustrated, the head is indicated generally at 6,-Fig. l and in itspreferred form herein shown comprises a plurality of radially disposedmembers, herein twelve, said radial members herein consisting of I-irons8. The

advantage of so large a number of radial members is that they lie atrelatively is preferable.

which they separate and to which said I-irons arerigidly secured by anysuitable means. Herein said I-irons are bolted to said plates 10 and 12by bolts 14 extending through suitable openings provided in the flangesof said I-irons and in said plates. The free ends of the I-ironspreferably project beyond the perimeters of the plates. The length ofthe I-irons projecting beyond the perimeters of the plates and thelength of the I-irons embraced between said plates will be soproportioned as to provide ample opportunity for a connection betweenthe I-irons and said plates which shall be of suflicient strength toresist any load or stresses to which said I-iron may be subjectedwithout the possibility of separation or loosening of the connection ofsaid plates and I-irons. In the embodiment of the invention hereinshown, wherein the I-irons are bolted by their flanges to said plates,the length of the I-irons embraced between said plates is of suflicientlength to provide space for the use of a number of bolts sufficient forthis purpose.

The plates 10 and 12and radial arms 8 might be integral, such as acasting for example, but I prefer the construction herein shown.

The plates 10 and 12 will preferably be provided with grout holes 16 and18 respectively, herein preferably located centrally of said plates. v

The head 6 may. be used in conjunction with one or more metal membersextending through it; any suitable reinforcing material or a metalcolumn, for example, said member or members being encased within theconcrete column. In Figs. 1 and 2 the head is shown as used inconjunction with a system of reinforcing rods 20, while in Figs. 3 and 4the head is shown as used in conjunction with a metal column 22, whichmay be of steel, cast iron or any other suitable metal and of anysuitable cross-section, such as an H- or I-iron, for example. Figs. 1and 2 the reinforcing metal rods 20 are shown as extending throughsuitable openings 24 preferably of the same shape as the cross-sectionof the rods 20 so as to fit the latter. They might extend through thegrout holes, but the former construction In Figs. 3 and I the steelcolumn 20 is shown as extending through the grout holes 16, 18.

It will be noted that the members or plates 10 and 12 provide bearingareas within the perimeter of the column as indicated at 26, 26, whichbearing areas take the loads transn'iitted from the floor panel.

It will also be understood by those skilled in the art that in aconstruction embodying this invention, when a load is applied at theends of the radial arms tensile stresses occur in the top plate 10 andcompression stresses in the bottom plate 12. Furthermore, in such casethere is a tendency for the radial members to tear away from the plates.These conditions are completely met or counteracted by the provision ofthe bearing areas indicated and the connection of the radial memberswith the plates to form a unit, whereby the tensile and compressionstresses caused by the loading of the arms are neutralized and theshearing stresses on a line at the junction of the column and the slabare resisted by the combined plates and radial members.

It will be noted that in the construction shown, the column orreinforcing rods being encased in the concrete, the stresses aretransmitted through the concrete casing into the steel column orreinforcing rods.

In some cases projections or bearing areas may be attached to the steelcolumn to re ceive the stresses from the concrete. Such projections orbearing areas are herein exemplified by angle irons 28 in Fig. 3, saidangles irons being rigidly secured to the column in any suitable manneras by bolts 29. Instead of these projections or bearing areas,orinconjunction therewith, a shelf may besecured to the column and thehead rested on said shelf. Such -a shelf is shown in Fig. 4, in the formof angle irons- 80 suitably. secured to the flanges of the column205many suitable manner as by bolts 32.

As will be readily. understood by those skilled in the art, by passingreinforcing members or rods 20 through the head, the head is anchored. Aload applied at A produces compression on the concrete as indicated bythe arrow at B, and in turn a tensile stress at the reinforcing member20 as indicated by the arrow C. Likewise a load fromabove tends tostabilize the structure and produce compression in the concrete at D-asindicated by the arrow.

Structures embodying my invention possess many advantages over thosehere-tofore used. They are simple and economical in construction andtheir use makes it pos sible to do away with the capitals usuallyemployed at the junction of the tops of interior columns with the underside of the slab or wallcolumn brackets. This representsa substantialgain in space and eliminates the unsightly capitals or bracketsheretofore considered necessary, so that my other;

invention is applicable to structures to be used for purposes for whichthe structures embodying the conical capitals or projecting wallbrackets heretofore used are unsuitable or not desirable.

It will be apparent to those skilled in the art that my invention isapplicable to columns and flat-slab constructions of all kinds and thatit in no way interferes with the usual reinforcing employed in floorsand columns and that any such reinforcing structure may be employed inconjunction with my invention. It will-also be apparcut that myinvention will not interfere with the use ofdrainage or other pipes inthe floor, the use of such pipes being perfeetly feasible within floorsof structures embodying my invention.

Itwill be apparent that it is not indispensable that all of the featuresof the in-' vention be used conjointly, since they may be used toadvantage separately in various combinations-and sub-combinations. Itwill also be understood that, while the invention is herein described asembodied in the de-' head encased in said slab and comprising two spacedmetal plates and a plurality of I-irons embraced between-said plates andrigid therewith, said members being radially disposed with respect tothe center of said plates and-at relatively small angles to each iother; and one or more metal members extending through an opening oropenings provided in said plates and-encasedinthe concrete above andbelow said plates.

tion, a concrete slab; a concrete column; a

head encased in said slab and comprising two spaced metal plates widerthan the column but having substantial bearing areas within theperiphery of the column; and a plurality of metal members of angularsection embraced between said plates and rigid therewith, said membersbeing radially disposed. with respect to the center of said plates andat relatively small angles to each and a metal column extending throughan openingprovided in said plates and encased in the concrete above andbelow said plates.

3. In a flateslab construction, in combination, a concrete slab; aconcrete column; a head encased in said slab and comprising two spacedmetal plates-wider than the column and having a central opening ofsmaller diameter than the column; and a plurality of metal membersembraced between said plates and rigid therewith, said members beingradially disposed with respect to the center of said plates andprojecting outwardly beyond the periphery thereof; a metal columnextending through said opening provided in said plates and encased inthe concrete above and below said plates; and a shelf projecting fromthe metal column and upon which rests said head.

4. In a flat-slab construct-ion, in combination, a concrete slab; aconcrete column; a

head comprising two spaced metal members wider than the column andpresenting bearing areas within the perimeter of said column and aplurality of longitudinal metal members embraced between said spacedmetal members and extending radially outwardly therefrom, saidlongitudinal metal members being rigid with said spaced metal members;and one or more metal members extending through sa1d head and encased 1nthe concrete above and below sa1d head.

5. In a flat-slab construction, in combination, a concrete slab; aconcrete column; a

head comprising two spaced metal plates and one or more metal membersextending 35 through said head and encased in the concrete above andbelow said head.

In testimony whereof I have signed my name to this specification.

ROBERT M. HARDISON.

